RESET-BRAIN: REhabilitation of SleEp and CogniTive Impairment in BReast Cancer Survivors Using an App-based Intervention

This trial (RESET-BRAIN) is testing an app-based program to help breast cancer survivors who are struggling with sleep problems (insomnia) and "chemo brain" (cognitive issues like memory and concentration difficulties after cancer treatment). The intervention is based on cognitive behavioral therapy for insomnia (CBT-I) and cognitive rehabilitation, delivered via a smartphone app. **You may be eligible if...** - You are 18 or older and have completed primary breast cancer treatment within the last 1–5 years (ongoing hormone therapy is fine) - You score above 10 on the Insomnia Severity Index OR meet criteria for insomnia disorder - You report significant memory or concentration problems on quality-of-life measures **You may NOT be eligible if...** - You have another sleep disorder (other than insomnia), neurodegenerative disease, or psychiatric condition that affects sleep or cognition - You are pregnant or on maternity leave - You have had a cancer recurrence or new cancer - You do not speak Danish well enough to participate - You have previous experience with CBT-I or shift work Talk to your doctor to see if this trial is right for you.